The direct liquid extraction-based surface sampling approaches, which are applicable to the analysis of soluble components at a surface, provide several advantages over other surface sampling approaches. These advantages include the ability to on-line process the extracted sample post sampling and prior to analysis. While some problems like the analysis of certain absorbent surfaces impede this approach, the most significant limitation is the achievable sampling spatial resolution. The achievable spatial resolution is connected to the geometric configuration of the sampling probe as this configuration, along with solvent, and surface properties define the area of the liquid junction formed between the probe and the surface. As currently understood, this liquid junction size determines the effective sampling spatial resolution of one embodiment of a surface sampling probe which utilizes coaxial capillaries. This design provides extremely good liquid junction control and perturbations in the positioning of the inner and outer capillaries during sampling allow for sample trapping, reaction, and injection. However, robustness considerations limit the ultimate spatial resolution of this geometry because if the inner diameter of the inner capillary is too small, then the capillary easily plugs the extract flow path. The best spatial resolution using a continuous flow, dual capillary, liquid-extraction based probe claimed 12 μm resolution using solvent delivery and spray capillaries of at least 70 μm in outer diameter. To achieve a spatial resolution better than 1 μm will most likely require that the size of the inner diameter of the spray capillary be made smaller. However, a capillary smaller than 50 μm will likely result in plugging problem which will ultimately limit the resolution that can be achieved.